EP4169489A1 - Stent - Google Patents

Abstract

The present invention relates to a stent for transluminal implantation in hollow organs, in particular in blood vessels, ureters, esophagus, colon, duodenum, airways or bile ducts, with an at least essentially tubular body which extends along a longitudinal direction and which is in a compressed state with a first cross-sectional diameter can be converted into an expanded state with an enlarged second cross-sectional diameter, the stent comprising a stent body made of a biostable material, characterized in that the stent body comprises a plurality of stent sections, which are in particular separate from one another and are preferably annular, and the stent has a support structure, which connects the stent sections together, wherein the support structure is formed from a bioresorbable material or comprises a bioresorbable material.

Description

The present invention relates to a stent for transluminal implantation in hollow organs, in particular in blood vessels, ureters, esophagus, colon, duodenum, airways or bile ducts, with an at least essentially tubular body which extends along a longitudinal direction. The stent can be converted from a compressed state with a first cross-sectional diameter into an expanded state with a second cross-sectional diameter that is larger than the first cross-sectional diameter. The stent includes a stent body made from a biostable material.

Stents are used to treat diseased hollow organs, for example when the hollow organs have narrowed (stenosis). Another area of application is the treatment of aneurysms.

For treatment, the stent is inserted in the compressed state via an insertion catheter to the site to be treated within the hollow organ, where the stent is expanded by dilatation or by self-expansion to a diameter that corresponds, for example, to the diameter of the healthy hollow organ, so that a supporting effect of the Hollow organ, in particular a vessel wall, is achieved.

Stents are usually intended to provide a high radial erection force in order to have a sufficiently large supporting effect, for example for a blood vessel. In addition, the stent should be able to adapt to deformations of the hollow organ, which are caused, for example, by the patient's movements. For this reason, the stent should be flexible in order to allow deformations in the longitudinal direction.

In addition, it is desirable to be able to place the stent in the hollow organ in a simple manner and at a precise location.

It is therefore the object on which the invention is based to provide an improved stent which, in particular, takes account of the aspects mentioned above.

This object is solved by a stent according to claim 1.

The stent according to the invention is characterized in that the stent body comprises a plurality of stent sections which are in particular separate from one another and are preferably annular. In addition, the stent according to the invention comprises a support structure which connects the ring-shaped stent sections to one another, the support structure being formed from a bioresorbable material or comprising a bioresorbable material.

The bioresorbable material is degraded or resorbed after being inserted into the hollow organ, so that after a certain period of time only the stent body made of the biostable material remains (permanently) in the hollow organ. The invention is therefore based on the finding that the stent sections of the stent body can be connected to one another by the support structure made of bioresorbable material and in this way can be fastened to one another, for example, in order to facilitate the insertion of the stent body into the hollow organ. After the dissolution or resorption of the bioresorbable material, the stent sections are no longer connected by the support structure, so that, for example, the flexibility of the stent can be increased along the longitudinal direction.

The support structure can therefore be a structure that remains in the body only temporarily and that is advantageously used during the insertion of the stent in is the hollow organ, but is not intended to remain in the hollow organ permanently.

The stent sections are preferably separate from one another. This means that the individual stent sections are not connected to one another by the biostable material of the stent body, but are only connected to one another, for example, by the support structure. The separate stent sections result in particularly high flexibility along the longitudinal direction after the support structure is eliminated. Furthermore, the stent sections can be ring-shaped, in which case, for example, the same distance can be present between the ring-shaped stent sections. Alternatively or additionally, however, any other shapes are also possible, for example with beveled and/or irregularly shaped stent sections.

The individual stent sections are in particular arranged in a row in succession along the longitudinal direction and preferably have a common axis which extends in the longitudinal direction.

Basically, the stent has a generally tubular body. That is, the longitudinal length of the stent is preferably greater (eg, at least two, five, ten, or thirty times greater) than the cross-sectional diameter of the stent. In the expanded state, the stent can have an empty, continuous lumen/volume in its interior, through which, for example, blood can flow. The stent can have a substantially constant cross-sectional diameter in the expanded state over its entire length in the longitudinal direction. Alternatively, the cross-sectional diameter can also change over the length of the stent, for example decrease continuously, in order to take account of a decrease in the diameter of the hollow organ.

The stent can be a self-expanding stent, which converts itself from the compressed state to the expanded state without the active application of force.

Alternatively, the stent can also be non-self-expanding and, for example, balloon-expandable. A balloon can then be placed inside the stent, the balloon being inflated under pressure, enlarging and, with this enlargement, urging and converting the stent from the compressed state to the expanded state ("balloon dilatation").

The biostable material can be a nickel-titanium alloy (nitinol), for example. The stent body is preferably formed from a material that stores a shape ("shape memory"), which assumes the stored shape above a limit temperature. In addition to the nickel-titanium alloy mentioned, the stent body can also be in the form of cobalt-chromium, cobalt-nickel or platinum-chromium alloys or can include such alloys. Furthermore, other suitable metals and/or metal alloys and/or metal materials are also possible.

The stent can in particular be a "covered stent" which is surrounded by a fabric material, for example. The stent can also include a stent graft. The stent graft is in particular an artificial vessel wall that can be used, for example, in the treatment of aneurysms. However, the stent described herein can also be a “bare stent”, ie a stent without a stent graft or material.

In particular, the support structure comprises a number of separate parts, ie the support structure preferably does not form a single cohesive structure.

The stent body may comprise a multiplicity of cells which are defined by bordering elements (e.g. so-called "struts") formed by the stent body. The bordering elements can be created by removing material when cutting the stent body from, in particular, tubular material, with the bordering elements or webs remaining in place. The bordering elements are preferably firmly connected to one another and in particular in one piece. Accordingly, the stent body does not comprise braided material, for example.

A cell may be connected to one or more other cells by one or more connection sections. A cell comprises the entire recess as well as its respective border elements, the connecting portions belonging to the border elements.

The cells of the stent body preferably form a convex polygon and in particular have a diamond shape. Alternatively, the cells can also be round, circular or elliptical. The shapes of the cells mentioned above can arise in particular when the cells are laid or pressed on a plane (the so-called unfolding). In the case of a convex polygon, all interior angles have an angle of ≤180°. Such cells can also be called "closed cells". The shape of a convex polygon and in particular the rhombus shape or also the elliptical shape can result in a high erection force and thus a high supporting effect of the stent.

In particular, most or all of the cells have the shape of a convex polygon, a diamond shape, a ring shape, an elliptical shape and/or a circular shape.

Alternatively or additionally, cells of the stent body can also form a concave polygon. In the case of the concave polygon, at least one interior angle can have an angle of >180°. For example, at least part of the border elements of a respective cell can have a zigzag shape. The flexibility of the stent can be further increased by such zigzag cells or generally by cells with the shape of a concave polygon. Also, most or all of the cells may have the shape of a concave polygon.

Furthermore, it is possible that the majority or all of the cells of the stent body have the same or a similar shape. A similar shape can be said to exist in particular when the bordering elements of two cells when they lie on top of one another have a maximum offset that does not exceed 10%, 20% or 30% of the length of the greatest extent of the cell in one spatial direction.

At least one of the stent sections preferably comprises a row of cells which follow one another in the circumferential direction of the stent and preferably form a closed ring running around in the circumferential direction of the stent. The ring, perpendicular to the longitudinal direction of the stent, preferably has an annular, closed cross section formed by the cells of the ring. Such a preferably closed ring running around in the circumferential direction can create an optimal radial erecting force and supporting effect of the stent or the stent body in the stent section. In principle, a stent section can be formed by any cells. In particular, a ring-shaped stent section can have exactly one single row or exactly two or three interconnected rows of cells. Having two or three interconnected rows of cells lengthens the stent section lengthwise but also provides increased deployment force.

Advantageous developments of the invention can be found in the description, the drawings and the dependent claims.

According to a first embodiment, the support structure is designed to hold the stent sections in a defined position relative to one another. The support structure thus fastens the stent sections so that their spacing and/or orientation remain the same in the expanded and/or compressed state (at least without the application of a major external force). A constant distance and/or orientation enables improved insertion at a target position that can be determined very precisely. During the resorption of the support structure in the hollow organ, a certain ingrowth of the stent sections usually takes place, so that the stent sections then remain in their respective position even without the support structure. As already mentioned, however, without the support structure, the flexibility along the longitudinal direction preferably increases. Alternatively or additionally, the flexibility of the stent body can be fundamentally improved, so the longitudinal extensibility and/or compressibility can be increased and/or the torsional capacity can be improved, but there is no relevant reduction in the radial erection force, i.e. the support effect.

In particular, the connection or attachment of the stent sections by the support structure can also be understood to mean that relative movements of the support structure and stent body or stent sections are still possible, but unintentional detachment of the support structure and stent body is prevented.

According to a further embodiment, the support structure is arranged at least essentially on the outside of the stent body. When used in the hollow organ, the outside of the stent body rests at least in regions on the tissue of the hollow organ. In particular, more than 50%, more than 80% or more than 95% of the material of the support structure can be on the outside and/or outside of the stent body. The support structure preferably does not protrude beyond an inner side of the stent body into the free lumen inside the stent, in order to avoid impairment of the blood flow through the free lumen, for example.

The parts of the support structure are therefore arranged in particular in such a way that they are pressed against the wall of the hollow organ or at least come to rest in the area of the wall of the hollow organ, so that during the resorption process it is avoided that fragments of the support structure, for example, get into the bloodstream and are washed away .

According to a further embodiment, the support structure comprises a plurality of rails which run at least essentially parallel to the longitudinal direction. The rails may preferably be attached to connecting portions of the cells of the stent body. The rails are more preferably each straight and run, for example, on the outside of the stent body. The forces required for inserting and/or releasing the stent into/from a catheter of an insertion set can be reduced by the splints. This simplifies both the preparation of the insertion process and the release of the stent in the hollow organ. The rails thus create an advantage when inserting the stent, then dissolve due to the bioresorbable material and do not impede the flexibility of the stent in the long term.

Alternatively or additionally, at least some rails can also have a spiral course along the longitudinal direction, i.e. at least partially run around an axis formed by the stent.

According to another embodiment, the rails are evenly distributed in the circumferential direction of the tubular body. This means that the rails are arranged uniformly, for example along the circumference of the stent body, when viewed in cross-section. From a central axis of the stent body seen, a rail can then be arranged at least eg every 30°, every 45° or every 60°.

According to a further embodiment, the rails have an equal length in the longitudinal direction. The length of the rails can correspond to the length of the stent body, for example. The rails can also be shorter than the stent body and, for example, only 30, 40, 50, 60 or 70% of the length of the stent body in the longitudinal direction. Alternatively or additionally, at least some of the rails can also be longer than the stent body.

According to a further embodiment, the rails have different positions as seen in the longitudinal direction. The rails can thus have different starting and/or ending positions in the longitudinal direction. For example, two rails can only partially overlap each other along the longitudinal direction. It is also possible for the rails to be at a distance from the ends of the stent body or to protrude beyond the ends of the stent body.

According to a further embodiment, at least one of the rails comprises at least one spring element which has increased flexibility compared to the flexibility of the rail in the area outside the spring element, with the spring element preferably being arranged between two stent sections. More preferably, the spring element is arranged centrally between two stent sections. The spring element increases the bendability or flexibility of the stent, particularly in the longitudinal direction, since the increased flexibility of the spring element allows the stent sections to move to a certain extent relative to one another. The spring element preferably comprises a tapered area and/or a zigzag shape and/or a meander shape, the increased flexibility of the spring element being achieved by the tapered area and/or the zigzag shape and/or the meander shape. Especially with the positioning between the stent sections, the stent sections can then be moved more flexibly relative to one another, as explained above.

According to a further embodiment, the support structure is attached to the stent body by means of a form fit and/or force fit. In particular, the support structure is attached to the stent body exclusively by means of a form fit and/or force fit. In addition, the positive and/or non-positive connection preferably takes place exclusively with the material of the stent body and the support structure, so no additional material is required, for example for gluing, soldering, welding and the like.

The connection of support structure and stent body by means of a form fit and/or force fit makes it possible to connect the biostable material to the bioresorbable material, although nitinol, for example, is practically impossible to weld to a bioresorbable material such as zinc. However, due to the attachments of the support structure to the stent body described herein, a sensible use in the hollow organ is then still possible.

The connection of the support structure and the stent body by means of a form fit and/or force fit can in particular take place in such a way that a recess with an undercut is provided in the stent body, with the support structure protruding into the undercut. For example, the recess with the undercut can be shaped approximately trapezoidal (e.g. as an isosceles trapezoid) in cross section, wherein the trapezoid can be open on its shorter base, whereby the undercut occurs in the region of the longer base.

The support structure material can be introduced into the area of the recess with the undercut and heated there, for example in order to liquefy it briefly. As a result, the material of the support structure in the area of the undercut rest against the stent body and in this way produce a form fit and possibly also a force fit.

According to a further embodiment, the stent body has a fastening projection for fastening the support structure to the stent body, around which the support structure is formed at least partially circumferentially. Preferably, the support structure can also run completely around the fastening projection. It is therefore a form-fitting connection between the stent body and the support structure. The support structure describes, for example, an arc (when partially encircling) or a loop (when fully encircling). It is therefore a form-fitting connection between the support structure and the stent body.

The support structure can preferably be flattened in the manufacturing process of the stent in the area of the attachment projection, for example to be level with the inside of the stent body and not to protrude into the lumen of the stent body.

According to a further embodiment, the fastening projection is arranged in a recess in the stent body and/or projects out of the recess. The recess can be circular or elliptical in cross section, for example, and accordingly form an eyelet in which the fastening projection is arranged and/or from which the fastening projection protrudes. The fastening projection arises in particular from the inner wall of the recess and protrudes (initially) into the recess. The support structure can then be supported against the inner wall of the recess when partially or completely running around the fastening projection, as a result of which a secure connection is created between the support structure and the stent body.

The fastening projection can, for example, be curved and, in particular, only partially protrude from the recess. The attachment boss preferably protrudes from the outside of the stent body so as not to impair the lumen inside the stent body.

According to a further embodiment, the stent body is hooked to the support structure for fastening the support structure, in particular by means of two fastening rings which engage in one another, with at least one of the fastening rings being open. For example, the support structure may include one or more closed attachment rings, while the stent body includes one or more open attachment rings. The fastening rings can then be connected to one another like chain links. Alternatively, the open attachment rings can also be provided on the support structure and the closed attachment rings on the stent body. The attachment rings are preferably washers, but other shapes are possible, e.g. oval, square, spoon-shaped (i.e. curved, especially with the same radius as the stent body). In principle, the shape of the fastening rings can be arbitrary, as long as a fastening ring of the stent body can engage in a fastening ring of the support structure.

With an open fastening ring, a slot can be provided which is wider than the thickness of the material of the closed fastening ring. However, the slot may have a maximum width of twice, three or five times the thickness of the material of the attachment ring.

The fastening by the fastening rings is also not a form-fitting connection. In general, the stent body can therefore be connected to the support structure via hooks and eyes.

According to a further embodiment, the stent body and support structure are hooked together by means of a barb guided through an opening. The opening can in particular be a closed fastening ring act as described above. In this case, the closed fastening ring can preferably be attached to the stent body. The barb may be formed of bioresorbable material and includes a rod with at least two rearward hook portions attached to the tip of the rod. The hook portions together can define a V-shape. During manufacture of the stent, the hook sections can be passed through the opening one after the other, after which the hook sections are prevented from being pulled out. The barb on the support structure can thus be used to attach the support structure to the stent body.

According to a further embodiment, the support structure comprises a plurality of cylinder segments inside the stent body. The cylinder segments are preferably in contact with the inner wall of the stent body. The cylinder segments are created by cutting a cylinder along the cylinder axis. The cylinder segments can have the shape of circular sectors or circular ring sections in cross section. When assembled, the circular ring sections can in particular form a hollow cylinder.

According to a further embodiment, the cylinder segments form a cylinder or hollow cylinder in the compressed state of the stent. During the transition to the expanded state, the cylinder segments then move away from one another and form, in particular, internal rails attached to the stent body. The cylinder segments can be attached to the stent body using the attachment options mentioned herein.

Alternatively or in addition to an internal hollow cylinder, it is also possible for the support structure to form an external hollow cylinder or an external tube around the stent body, in particular in the compressed state.

In particular, the support structure on the inside can have a different degradation behavior than the support structure on the outside, for example the support structure on the inside can be biodegradable more quickly than the support structure on the outside. For example, the inner support structure may be fully degradable within minutes or hours, while the outer support structure may take days or weeks to fully degrade.

According to a further embodiment, the support structure comprises a plurality of recesses or indentations in which stent sections of the stent body come to rest. In this case, the support structure can in particular be external, i.e. arranged on the outside of the stent body. The recesses can also be referred to as positioning recesses. The recesses/indentations can be adapted for the stent sections, so that thickenings of the support structure are then present between the stent sections. The recesses or indentations hold the stent sections, and thus the stent body, in place. The recesses or indentations can thus also be used to achieve precise positioning of the individual stent sections when they are inserted into the hollow organ.

According to a further embodiment, at least two stent sections of the stent body are connected to one another by connecting elements formed from material of the stent body, parts of the support structure being attached to the connecting elements in order to reinforce the connecting elements. In this embodiment, the stent sections are not formed separately from one another, at least in part. To reinforce the connecting elements using the bioresorbable material, the connecting elements can be covered with the bioresorbable material, for example. Alternatively or additionally, the connecting elements can have, for example, a groove or another depression into which the bioresorbable material of the support structure is introduced. When the stent is inserted into the hollow organ, the bioresorbable material then causes an increased Rigidity of the connecting elements, which in turn results in good positioning properties. After resorption of the bioresorbable material, the connection elements are then more flexible due to the omission of the additional material, which then advantageously increases the flexibility of the stent.

According to a further embodiment, the connecting elements have a thinner and/or tapered material, at least in regions. In particular, the material is thinner and/or tapered in comparison to the stent sections of the stent body. The thinner and/or tapered material refers only to the biostable material of the stent body. Thinner means, for example, less area and/or material in cross-section than in cross-section, e.g., through a strut in a stent section. Together with the material of the support structure, the connecting element can be just as thick or even thicker than the biostable material in the area of the stent sections.

According to a further embodiment, the support structure presses against the stent body in at least one fastening recess of the stent body in order to fasten the support structure to the stent body by means of a force fit. The support structure can preferably be pressed with the stent body in some areas. The fastening recess can be, for example, a hole or through-hole in the stent body, into which the bioresorbable material of the support structure is pressed. The pressing can be done, for example, by a press mandrel, as explained in more detail below. As a result, the bioresorbable material of the support structure can press against the inner wall of the fastening recess on all sides, with a recess also remaining in the bioresorbable material centrally in the fastening recess.

According to a further embodiment, the stent body is formed from a biostable material that stores a shape Takes form, wherein the biostable material is or comprises, for example, nitinol, as already explained above.

In addition, the stent can comprise several x-ray markers, in particular made of tantalum, for easier positioning under x-ray observation. The x-ray markers can be attached, for example, to the ends of the stent body and/or the support structure, viewed in the longitudinal direction. X-ray markers on the support structure can be formed in particular by material thickening of the bioresorbable material. At least one x-ray marker preferably extends in the longitudinal direction from at least one end of the stent body, in particular in the form of an eyelet, the x-ray marker having an asymmetrical shape. A marker can be a section of the stent body which has increased radiopacity, i.e. is particularly clearly visible in an X-ray image. In particular, the marker can be an eyelet that is filled or covered with the aforementioned tantalum, for example.

According to a further embodiment, the bioresorbable material comprises zinc. The bioresorbable material preferably consists of zinc and silver or comprises zinc and silver. In particular, the bioresorbable material contains 90.0 to 99.95% by mass of zinc and 0.05 to 10.0% by mass of silver. Such a bioresorbable material can, for example, be broken down by the body in the bloodstream within a few weeks.

Alternatively, the bioresorbable material can also include or consist of a polymeric material, for example polylactic acid (PLA) or poly-L-lactic acid (PLLA). The bioresorbable material can also include a magnesium alloy or consist of a magnesium alloy. By using zinc or a zinc alloy as described above, the radiopacity of the stent can be increased in comparison to PLA, PLLA or magnesium alloys but to be increased. The bioresorbable material can also be referred to as biodegradable material.

Combinations of different bioresorbable materials are also possible. Also, the support structure may include one or more different bioresorbable materials and one or more radiopaque materials.

In particular, the stent body and/or the support structure can also be mixed with or coated with an active substance. Such an active ingredient can have an antiproliferative effect in order to prevent the stent from becoming overgrown with tissue. For example, antiproliferatives from the Limus group, statins, P2Y12 antagonists or thrombin antagonists can be used as the active ingredient.

Another object of the invention is a stent system with a stent of the type described herein and a catheter, in which the stent is accommodated or can be accommodated in the compressed state. The stent is preferably surrounded by a sheath in the catheter. When inserting the stent into the catheter, i.e. when preparing the stent system, the force required for inserting it into the catheter can be reduced, in particular by rails of the support structure. Likewise, the force required for release from the catheter or the sheath can be reduced, which enables easier handling of the stent system. The catheter can preferably have depressions on an inner wall, in which the rails of the stent or, in general, the support structure come to rest in order to be able to position the stent in the catheter in a simple manner.

The catheter can be part of what is known as an insertion kit, with the insertion kit having in particular handling means for moving and releasing the stent in the hollow organ.

In particular, the catheter may be configured to draw the stent sections closer together upon deployment to facilitate deployment and, in particular, to reduce the force required for deployment. Alternatively or additionally, it is possible that the catheter is designed to cause the stent and in particular the stent body to rotate when the stent is released, so that the cells of the stent mesh in the manner of gear wheels, i.e. that one tip of a cell in each case bulge between two cells ("peak to valley"). In this way, a more continuous surface of the stent can be created, through which rotating the catheter a few degrees alternately to the right and left can be avoided (which may otherwise be necessary if the tips of cells of adjacent stent sections are precisely aligned).

Alternatively or additionally, the catheter can also be designed so that the distance between the stent sections can be adjusted when released, e.g. in three steps (tight, normal, wide). Such a change in distance can be made possible by the elasticity of the support structure.

The contraction and/or twisting of the stent sections can take place, for example, by holding the stent, in particular at the ends of the stent, by means of two separate holding mechanisms of the catheter, with the two holding mechanisms being moved and/or twisted in relation to one another.

Another object of the invention is a method for producing a stent with an at least essentially tubular body which extends along a longitudinal direction and which can be converted from a compressed state with a first cross-sectional diameter into an expanded state with an enlarged second cross-sectional diameter, the stent a stent body made of a biostable material, the stent body comprising a plurality of stent sections, in particular separate from one another, preferably ring-shaped and the stent has a support structure which connects the ring-shaped stent sections to one another, the support structure being formed from a bioresorbable material or comprising a bioresorbable material, in which method a force is exerted on the support structure already in contact with the stent body in order to prevent deformation of the support structure. The deformation can be, for example, a loop of the support structure being flattened in order to push parts of the support structure that protrude into the interior space out of the interior space.

According to one embodiment of the method, when the force is exerted, the support structure is pressed with the stent body in order to attach the support structure to the stent body by means of a force fit. The pressing preferably takes place in a fastening recess.

Generally speaking, the support structure can be pressed to the stent body at one or more points, with the support structure being slipped over material of the stent body in a pressed area, for example, and then pressed.

According to a further embodiment of the method, an inner tube is inserted into the stent body as a counter bearing during the pressing process. The pressing can be done, for example, by a press mandrel with a cone shape. During the pressing, an inner tube can be introduced inside the stent body as a counter bearing, so that the stent body does not collapse due to the pressure of the pressing mandrel. The inner tube can have a recess through which the press mandrel can be pushed into the interior of the inner tube during pressing. The support structure can be pressed annularly and/or on all sides against the walls of the fastening recess by the press mandrel, with in particular an area without material of the support structure in the center of the fastening recess arises. The area without material occurs after removing the press mandrel, where the press mandrel was located during pressing.

A durable connection between the biostable material and the bioresorbable material can be created by pressing the supporting structure and the stent body.

The statements made regarding the stent according to the invention apply correspondingly to the stent system according to the invention and the method according to the invention. This applies in particular with regard to advantages and embodiments. In addition, it goes without saying that all of the embodiments mentioned herein can be combined with one another, unless something to the contrary is explicitly stated.

Fig. 1

schematisch einen Stent mit einem Stentkörper und einer Stützstruktur gemäß einer ersten Ausführungsform;

Fig. 2

schematisch die Zellen eines Stents und Schienen der Stützstruktur gemäß einer zweiten Ausführungsform;

Fig. 3

schematisch die Zellen eines Stents und Schienen der Stützstruktur gemäß einer dritten Ausführungsform;

Fig. 4

schematisch die Verbindung der Stützstruktur mit dem Stentkörper gemäß einer vierten Ausführungsform;

Fig. 5

schematisch die Befestigung der Stützstruktur mit Zellen des Stentkörpers gemäß einer fünften Ausführungsform;

Fig. 6

schematisch die Verbindung der Stützstruktur mit dem Stentkörper gemäß einer sechsten Ausführungsform;

Fig. 7

einen Stentkörper und eine Stützstruktur, welche als in Zylindersegmente geteilter Hohlzylinder im Inneren des Stentkörpers ausgebildet ist (siebte Ausführungsform);

Fig. 8

schematisch Verbindungselemente zwischen Stentabschnitten, welche durch bioresorbierbares Material verstärkt sind (achte Ausführungsform); und

Fig. 9

eine Stützstruktur gemäß einer neunten Ausführungsform, wobei die Stützstruktur Vertiefungen umfasst, in welchen Stentabschnitte zu liegen kommen.

The invention is described below purely by way of example with reference to the drawings. Show it:

1

schematically a stent with a stent body and a support structure according to a first embodiment;

2

schematically the cells of a stent and splints of the support structure according to a second embodiment;

3

schematically the cells of a stent and splints of the support structure according to a third embodiment;

4

schematically the connection of the support structure to the stent body according to a fourth embodiment;

figure 5

schematically the attachment of the support structure with cells of the stent body according to a fifth embodiment;

6

schematically the connection of the support structure to the stent body according to a sixth embodiment;

7

a stent body and a support structure, which is designed as a hollow cylinder divided into cylinder segments inside the stent body (seventh embodiment);

8

schematic connection elements between stent sections, which are reinforced by bioresorbable material (eighth embodiment); and

9

a support structure according to a ninth embodiment, wherein the support structure comprises depressions in which stent sections come to lie.

1 shows a stent 10 of a first embodiment in the expanded state. The stent 10 has a tubular shape and extends along a longitudinal direction L. The stent comprises a tubular stent body 12, the stent body 12 being connected to a support structure 14. In the 1 the support structure 14 is shown in the form of a plurality of rails 16 .

The stent body 12 is formed from a biostable material such as nitinol. The support structure 14, on the other hand, consists of a bioresorbable material, for example a zinc alloy.

For the other embodiments, essentially only the differences from the embodiment of FIG 1 explained.

2 shows a second embodiment of the stent 10. 2 shows a section of a development of the stent 10. The stent body 12 is formed from cells 18. FIG. The cells 18 each have a diamond shape and are formed from web-like bordering elements 20 .

The stent 10 can also have additional cells 18 which are not shown in the figures.

In the 2 Cells 18 shown above are each marked with the in 2 cells 18 shown below so as to create the tubular shape of the stent body 12. The cells 18 of the stent 10 each form separate annular stent sections 22. Each stent section 22 comprises a series of cells 18 which are circumferentially interconnected. The cells 18 of a stent section 22 are each connected to the cells 18 that are adjacent in the circumferential direction via two connecting sections 24 .

The rails 16 are each coupled to the stent body 12 in the region of the connecting sections 24 . The rails 16 are elongate and straight and extend over the entire length of the stent body 12. The individual stent sections 22 themselves are only connected to one another via the rails 16 of the support structure 14.

3 12 shows a third embodiment of the stent 10. The third embodiment differs from the embodiment according to FIG 2 in that the rails 16 each have a spring element 26 between two stent sections 22 . The spring element 26 includes a taper 28 which is part of a meandering structure 30 . The spring elements 26 allow a certain mobility of the stent sections 22 among one another.

4 FIG. 12 shows a fourth embodiment, in which a possibility for connecting the support structure 14 to the stent body 12 is shown. 4 12 shows recesses 32 made in connecting sections 24, with a fastening projection 34 protruding into the recesses 32. FIG. Loops 36 or bends 38 of the support structure 14 can then be placed around the attachment projections 34 in order to attach the support structure 14 to the stent body 12 .

In the figure 5 The fifth embodiment shown also includes fastening projections 34 around which loops 36 of the support structure 14 are placed. In contrast to the embodiment of 4 the fifth embodiment comprises elliptical cells 18. In addition, the fifth embodiment shows rails 16 which are only attached to (seen in the longitudinal direction L) every other stent section 22, respectively. In addition, the rails 16 are shorter than the length of the stent body 12 .

6 12 shows a sixth embodiment of the stent 10. In the sixth embodiment, the support structure 14 is connected to the stent body 12 by means of attachment rings 40. FIG. Both the stent body 12 and the support structure 14 have fastening rings 40 . The attachment rings 14 of the stent body 12 can be open and have a slot (not shown) through which the attachment ring 40 of the support structure 14 can engage in the attachment ring 40 of the stent body 12 . Accordingly, the attachment rings 40 of the support structure 14 can be closed attachment rings 40 .

In the embodiment according to 6 the individual stent sections 22 can also be connected to one another by material of the stent body 12, more precisely by connecting elements 42. The connecting elements 42 each extend from one end of a diamond-shaped cell 18 of a stent section 22 to one end of a cell 18 of a directly adjacent stent section 22.

7 shows a seventh embodiment of a stent 10 in the expanded state. 7 1 shows a view in the direction of the longitudinal axis L. Within the stent body 12, the support structure 14 comprises a plurality of cylinder segments 44 which form a hollow cylinder in the compressed state. The cylinder segments 44 form internal rails 16 within the stent body 12.

8 10 shows an eighth embodiment of the stent 10, in which the stent sections 22 are connected by connecting elements 42. FIG. In the upper area of the 8 a part of a development of the stent 10 is shown for this purpose (top view). In the lower part of 8 a side view of a connecting element 42 is shown. The connecting element 42 is formed from biostable material of the stent body 12 and is reinforced by bioresorbable material of the support structure 14 . The material of the support structure 14 used for reinforcement is accommodated in a receptacle 46 of the connecting element 42, the receptacle 46 being able to be formed by a cutout in the connecting element 42, for example.

9 shows a ninth embodiment of the stent 10, wherein a schematic side view of the stent 10 is shown. The stent 10 in turn comprises a plurality of stent sections 22 which are connected to a support structure 14, wherein in 9 a rail 16 of the support structure 14 is shown. The rail 16 includes a plurality of positioning recesses 48 in which the stent sections 22 come to rest and are thus held in predetermined positions relative to one another. A thickening 50 of the rail 16 is provided between the positioning recesses 48 .

As explained above, the different embodiments can be combined with one another. For example, the positioning recesses 48 can also be integrated into the rails 16 of the previous embodiments. It is also possible to use different connection methods between the stent body 12 and the support structure 14 to combine with each other.

All of the embodiments have in common that the support structure 14 increases the stability of the stent 10 when it is inserted into a hollow organ. The support structure 14 is only temporarily present after insertion and is resorbed, with the advantage of increased flexibility of the stent 10 being provided after resorption.

Reference List

10

stent

12

stent body

14

support structure

16

rail

18

cell

20

border element

22

stent section

24

connection section

26

spring element

28

rejuvenation

30

meandering structure

32

recess

34

mounting boss

36

loop

38

arc

40

mounting ring

42

fastener

44

cylinder segment

46

Recording

48

positioning recess

50

thickening

Claims (15)

Stent (10) for transluminal implantation in hollow organs, in particular in blood vessels, ureters, esophagus, colon, duodenum, airways or bile ducts, having an at least essentially tubular body which extends along a longitudinal direction (L) and which is in a compressed state a first cross-sectional diameter can be converted into an expanded state with an enlarged second cross-sectional diameter, wherein the stent (10) comprises a stent body (12) made of a biostable material, characterized in that the stent body (12) (12) comprises a plurality of stent sections (22), in particular separate, preferably ring-shaped, and the stent (10) has a support structure (14) which connects the stent sections (22) to one another, the support structure (14) being formed from a bioresorbable material or comprising a bioresorbable material. Stent (10) according to claim 1, the support structure (14) being designed to hold the stent sections (22) in a defined position relative to one another
and or wherein the support structure (14) is arranged at least substantially on the outside of the stent body (12). Stent (10) according to at least one of the preceding claims, wherein the support structure (14) comprises a plurality of rails (16) which run at least substantially parallel to the longitudinal direction, preferably the rails (16) are evenly distributed in the circumferential direction of the tubular body and/or have the same length in the longitudinal direction and/or have different positions in the longitudinal direction. Stent (10) according to at least claim 3,
wherein at least one of the rails (16) comprises at least one spring element (26) which has increased flexibility compared to the flexibility of the rail (16) in the area outside of the spring element (26), the spring element (26) preferably between two annular stent sections (22) is arranged, more preferably centrally between two annular stent sections (22). Stent (10) according to at least one of the preceding claims,
wherein the support structure (14) is attached to the stent body (12) by means of a form fit and/or force fit. Stent (10) according to at least one of the preceding claims, wherein the stent body (12) has a fastening projection (34) for fastening the support structure (14) to the stent body (12), around which the support structure (14) is formed at least partially circumferentially, wherein the fastening projection (34) is arranged in particular in a recess (32) of the stent body (12) and/or projects out of the recess (32). Stent (10) according to at least one of the preceding claims, wherein the stent body (12) is hooked to the support structure (14) for attachment of the support structure (14), in particular by means of two interlocking Fastening rings (40), at least one of the fastening rings (40) being open, the stent body (12) and the support structure (14) being hooked together in particular by means of a barb guided through an opening. Stent (10) according to at least one of claims 1, 2 and 4 to 11, wherein the support structure (14) comprises a plurality of cylinder segments (44) inside the stent body (12), the cylinder segments (44) forming in particular a cylinder or hollow cylinder in the compressed state of the stent. Stent (10) according to at least one of the preceding claims,
wherein the support structure (14) comprises a plurality of recesses (48) and/or depressions in which stent sections (22) of the stent body (12) come to rest. Stent (10) according to at least one of the preceding claims,
wherein an inner support structure (14) has a different degradation behavior than an outer support structure (14), for example the inner support structure (14) is more rapidly biodegradable than the outer support structure (14). Stent (10) according to at least one of the preceding claims,
wherein at least two stent sections (22) of the stent body (12) are connected to one another by connecting elements (42) formed from material of the stent body (12), wherein parts of the support structure (14) are attached to the connecting elements (42) in order to connect the connecting elements (42 ) to reinforce. Stent (10) according to at least one of the preceding claims, wherein the support structure (14) presses against the stent body (12) in at least one attachment recess of the stent body (12) in order to attach the support structure (14) to the stent body (12) by frictional locking. Stent system with a stent (10) according to at least one of the preceding claims and a catheter in which the stent (10) is or can be accommodated in the compressed state,
the catheter preferably having indentations on an inner wall, in which the support structure of the stent (10) comes to rest. Stent system according to claim 21 or 22,
wherein the catheter is designed to set or change a distance between the stent sections (22) when released and/or to rotate the stent sections (22) in relation to one another when released. Method for producing a stent with an at least essentially tubular body which extends along a longitudinal direction (L) and which can be converted from a compressed state with a first cross-sectional diameter into an expanded state with an enlarged second cross-sectional diameter, wherein the stent (10) comprises a stent body (12) made of a biostable material, wherein the stent body (12) comprises a plurality of stent sections (22), in particular separate from one another, preferably ring-shaped, and the stent (10) has a support structure (14) which connects the annular stent sections (22) to one another, the support structure (14) being formed from a bioresorbable material or comprising a bioresorbable material, in which method a force is exerted on the support structure (14) already in contact with the stent body (12) in order to cause deformation of the support structure (14).

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